External plugs are a get-you-home, not a repair
A plug pushed in from outside without removing the tyre seals the hole but does nothing about the damage to the casing, and it cannot be inspected. A proper repair means the tyre comes off the rim, the inside is examined for the damage the object did on its way in, and a combined plug and patch seals it from the inside. That is a permanent repair. The other is not.

